Detecting stray voltages used by utility companies is a technology that may be promising for neural reading outside of the body. The system treats objects as antennas and uses a very sophisticated receiver and DSP techniques to capture objects with as little as 1V rms from 6 meters away. Since it is configured for line voltage frequencies (whose power frequencies is very close to that of neural pathways apparently…) I would image the tech would be a good start. Namely the concept and DSP algorithms.

The company is called Power Survey Company and the truck equipped device is the SVD2000.